Electronic devices, such as mobile phones, smart phones, tablet computers, laptop computers etc. often have a casing. A surface of the casing may be treated by a process such as Electrophoretic Deposition (ED) or Micro-Arc Oxidation (MAO).
Electrophoretic Deposition is a process in which a substrate is placed in a fluid and a potential difference is applied to cause charged particles in the fluid to be deposited on the substrate. ED may be used to impart certain desired properties, such as hardness or toughness, or a certain desired appearance to the substrate.
Micro Arc Oxidation (MAO), also known as plasma electrolytic oxidation, is a process for generating oxide coatings on a metal substrate. MAO involves applying a relatively high electric potential difference (e.g. 200V) while the substrate is placed in an acidic or alkaline electrolyte. The electric potential causes electric discharges which result in in localized plasma reactions in conditions of high temperature and pressure that modify the oxide layer. MAO can result in a protective oxide layer having improved toughness and wear resistance.